MC68HC05C8A Datasheet, PDF (52/158 Pages) Motorola, Inc – Microcontrollers

Low-Power Modes
STOP
STOP OSCILLATOR
AND ALL CLOCKS
CLEAR I BIT
WAIT
OSCILLATOR ACTIVE
TIMER CLOCK ACTIVE
PROCESSOR CLOCKS STOPPED
CLEAR I BIT
N
RESET
RESET
N
EXTERNAL
Y
INTERRUPT
N
(IRQ)
Y
EXTERNAL
INTERRUPT
N
(IRQ)
Y
Y
TIMER
INTERRUPT
Y
TURN ON OSCILLATOR
WAIT FOR TIME
DELAY TO STABILIZE
1. FETCH RESET VECTOR
OR
2. SERVICE INTERRUPT
A. STACK
B. SET I BIT
C. VECTOR TO
INTERRUPT
ROUTINE
RESTART
PROCESSOR CLOCK
1. FETCH RESET VECTOR
OR
2. SERVICE INTERRUPT
A. STACK
B. SET I BIT
C. VECTOR TO
INTERRUPT
ROUTINE
N
SCI
INTERRUPT
Y
N
SPI
N
INTERRUPT
Figure 6-1. Stop/Wait Mode Flowchart
6.3 Stop Mode
The STOP instruction places the microcontroller unit (MCU) in its lowest-
power consumption mode. In stop mode, the internal oscillator is turned
off, halting all internal processing, including timer operation.
During stop mode, the TCR bits are altered to remove any pending timer
interrupt request and to disable any further timer interrupts. The timer
prescaler is cleared. The I bit in the condition code register is cleared to
enable external interrupts. All other registers and memory remain
Technical Data
52
MC68HC05C8A • MC68HCL05C8A • MC68HSC05C8A — Rev. 5.0
Low-Power Modes
MOTOROLA